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However, sometimes the number of chromosome sets doubles from one generation to the next: one diploid organism suddenly becomes a tetraploid -- i.e. it has four sets of chromosomes.

Tetraploid rock-cresses have managed to overcome the disadvantage of genome duplication and can establish themselves in independent populations.

In earlier studies of such tetraploid sand rock-cress populations, the researchers identified genes associated with the plant's fertility for which novel variants had evolved in the tetraploids.

What's more, in established tetraploid populations of sand rock-cress, the genes in question are often slightly different to the versions found in diploid individuals.

"In other words, evolution has found a way to minimally vary the two genes in such a way that tetraploid individuals are fertile," Bomblies says.